A computer-aided semen analysis (CASA) was used to allow digitizing the motion of the spermatozoon. This procedure allows an objective means of judging semen quality, especially the translational movements of spermatozoa. Forty-three couples were included in the study. The average age of the male was 35.5 +/- 4.7 years and that of the female was 32.7 +/- 4.7 years. The average duration of infertility was 3.8 +/- 2.3 years. Using multiple linear regression analysis of 26 prognostic variables, a cluster of 8 variables significantly predicted pregnancy maximally. The 8 variables and the resultant multiple correlation coefficients were used to generate a multiple regression equation which allowed the correct separation of the population into fertile and infertile couples. The mean pregnancy predictor values of the fertile and infertile populations were significantly different using the analysis of variance.